1. Field of the Invention
The present invention is related to rotary seals for use with relatively rotatable parts for fluid retention. More particularly, the present invention is related to a backup ring that is configured to increase the ability of a rotary seal to withstand differential pressure.
2. Description of the Related Art
The use of resilient rotary seals for establishing sealing between relatively rotatable machine components for fluid retention is known. The differential pressure that such resilient rotary seals can retain is limited by the extrusion resistance of the material used in the construction of the seal, and is also limited by the size of the extrusion gap clearance that exists between the seal housing and the mating relatively rotatable surface. The size of the extrusion gap clearance also influences interfacial lubrication of the seal.
The backup rings that are used with static seals and with reciprocating seals are unsuitable for use with rotary seals that are retaining significant differential pressure due to liabilities such as high friction, high wear, material flow, and damaging frictional heat.